AND GEOLOGICAL RELATIONS OF CERTAIN HOT SPRINGS. 
591 
I found it to be 90 o, 2 (Crichton), and on the 24th only 88 0, 8. The spring of La Hon- 
talade is about sixty or eighty feet higher : it is rather copious. 
Troughton. Reduced. 
July 28. — La Hontalade . . . 69 o, 0 68 0, 5 
V. Bareges. 
A. Geological Position . — In order to treat of the springs with more connexion, we 
have anticipated, in a great measure, what we have to state on this subject. The 
town of Bareges is seated on the bank of the torrent which occupies the Valley of 
Bastan. It is entirely surrounded by clay slate formations, but these, near Bareges, 
are concealed by immense alluvial deposits, which are in a great measure derived 
from the neighbouring elevations, which annually devastate the town with mud ava- 
lanches. Consequently we can neither trace the proper rise of the springs, nor are 
they well situated for affording permanent results. They have frequently been lost, 
owing to subsidence or other changes in the alluvial soil ; and in one remarkable in- 
stance a spring was recovered after many fruitless attempts by judicious boring : this 
spring is called the Source Polard, in honour of its re-discoverer. From what has 
been said in speaking of St. Sauveur, it will be seen that 1 think it reasonable to con- 
clude that the springs of Bareges owe their origin to the altered slate rocks in the 
vicinity, and more remotely to the granite of the Neouvielle, which probably pro- 
duced the alteration. 
B. Specialties of the Springs. — The waters of Bareges are in such request, and the 
supply is so inadequate to the demand, that they are almost all husbanded in cisterns, 
in which the baregine, or fatty matter, may be collected. Hence in general these 
springs are ill adapted for our experiments, especially when we consider the liability 
to change, owing to the alluvial soil. There is one spring, however, of much interest, 
Le Tambour, or Grande Douche. This flows in a copious constant stream from a 
spout in a vertical wall ; and M. Balard, physician at Bareges, assured me that this 
was the origin of the spring, and that no reservoir intervenes. The Source Polard I 
examined in the built cistern into which it rises : this, too, may be considered as a 
satisfactory experiment. The other two, the Bain de f Entree and Bain de la Cha- 
pelle, were taken at the cocks through which they flowed into the baths. 
C. Temperatures of the Springs. — Height of Bareges 4163 feet (Reboul and Vidal). 
On account of their celebrity we have more numerous records of the temperatures 
of these than perhaps of any other springs. There were formerly five Douches in- 
stead of one, so that the value of the comparison is in some degree lost. The Tam- 
bour, or principal spring, which was formerly called Le Grand Bain # , seems to have 
remained remarkably constant for almost a century. Two observers (Meighan in 
1739, and Secondat in 1750,) seem to have observed it with care; and, what is very 
* On the authority of M. Balard. 
